The present disclosure relates to an electric component-mounted substrate.
Since electronic component modules such as communication modules, wireless LANs and tuners are mounted on electric devices including cell phones, the modules have been heretofore required to be small and thin.
The electric component module, which usually has a few or several ICs for processing signals and the like, and dozens of passive components such as C and R and other odd-form component, is mounted on a mother board.
As to the electric component module, there are electric component-mounted substrates in which electric components are mounted on a front face and a back face of a base substrate. In an example of such substrates, a ring-shaped substrate, which surrounds the electric components, is formed on the front face or the back face of the base substrate, and the electric components are connected in a space (cavity) inside the ring.
Because it is difficult to form such a cavity structure in a process for producing a buildup substrate, the cavity structure is generally formed by connecting the ring-shaped substrate onto the front face of the base substrate. The electric components are connected to the base substrate after the cavity structure is formed.
However, because, in this method, the cavity structure is formed on the base substrate before the connection of the electric components, there is a problem that because the cavity structure hinders feeding of a connecting material such as a solder, the connecting material could not be fed by a simple method such as printing with a metal mask or bonding of an anisotropic electroconductive film. Accordingly, because the method for feeding the connecting material is limited to a method using a dispenser, the connecting material is limited to a material having excellent dischargeability from the dispenser. In addition, it is difficult to feed the connecting material in the form of fine patterns.
See, Patent Documents JP-A H11-45904, JP-A 2000-105388, JP-A 2002-93933, JP-A 2002-359264, and JP-A 2005-32952.